WHOAH! Just noticed this, no wonder it's totally available!
*Alerts and Important Information*
These are hike-in Tent sites. After registering at El Moro Canyon Park office, you will hike 3 strenuous miles to the campground.
Just so you know - the hike in sites are in the wooded canyons of El Morro about 3 miles from the beach. The Beach Cottages are the only "camping" on the beach in Orange County. For RV's or vehicle (roof-top tent, but no ground tents) there is always Huntington City or State Beaches (parking lot adjacent to the beach).
All of the developed beach campgrounds in So Cal are State facilities and reservations can be made 365 days in advance (and usually are!).
Good Luck!